feature-rc/SIENTIAPDE-2164 - refactor: centralize prediction metadata write in a dedicated activity; REPEAT now writes metadata too

laborious/activities/prediction_metadata.py

@@ -0,0 +1,132 @@
+from temporalio import activity, workflow
+
+with workflow.unsafe.imports_passed_through():
+    from typing import Any
+
+    from bson import ObjectId
+    from sientia_do.notifications.handlers import CoreNotificationHandler as NotificationHandler
+    from sientia_do.observability.logger import Logger
+    from sientia_do.observability.metrics_controller import MetricsController
+    from sientia_do.observability.sientia_monitoring import SientiaMonitoring
+    from sientia_do.repository.mongodb_repository_sync import MongoDBRepository
+
+
+class PredictionMetadata(SientiaMonitoring):
+    """
+    Centralized, best-effort writer for prediction gate metadata (triggered filter, policy,
+    counter) to MongoDB.
+
+    Gates only compute and return a metadata document; they never write it themselves. Keeping
+    the write here, instead of in each gate, puts the one real write point in the subworkflow
+    that's about to persist a `predictions` row — the only place that reliably knows whether one
+    is being written at all — and lets other metadata sources reuse the same activity instead of
+    duplicating write logic wherever they originate.
+    """
+
+    mongo_repository: MongoDBRepository | None = None
+    _PREDICTION_METADATA_COLLECTION = 'prediction_metadata'
+
+    def __init__(
+        self,
+        mongo_repository: MongoDBRepository | None = None,
+        logger: Logger | None = None,
+        notification_handler: NotificationHandler | None = None,
+        metrics_controller: MetricsController | None = None,
+    ):
+        """
+        Initialize the prediction metadata writer.
+
+        Args:
+            mongo_repository: MongoDB, where gate metadata (triggered filter, policy, counter) is
+                written best-effort. `None` is a valid state (see `write_prediction_metadata`).
+
+        Raises:
+            Exception: If BaseActivity initialization fails
+        """
+        self.mongo_repository = mongo_repository
+        SientiaMonitoring.__init__(
+            self,
+            logger=logger,
+            notification_handler=notification_handler,
+            metrics_controller=metrics_controller,
+        )
+
+    def close(self) -> None:
+        """
+        Close the prediction metadata writer and clean up resources.
+        """
+        if self.mongo_repository is not None:
+            try:
+                self.mongo_repository.close()
+            finally:
+                self.mongo_repository = None
+        SientiaMonitoring.shutdown(self)
+
+    def __del__(self):
+        self.close()
+
+    @activity.defn(name='write_prediction_metadata')
+    def write_prediction_metadata(self, input_data: dict[str, Any]) -> str | None:
+        """
+        Best-effort write of one or more gate metadata documents to Mongo, combined into a single
+        `prediction_metadata` document.
+
+        Implements both business rules for this feature in one place:
+        - The prediction write must never be blocked or failed by a metadata write. A failed
+          `insert(...)` is swallowed, never re-raised, logged here with call-site context (which
+          `mongo_repository.insert(...)` itself can't know) — matching how `storage.py`'s
+          `cleanup_minio_objects_expired` also logs again at the call site even though the
+          repository already logs internally and emits its own Prometheus metric
+          (`MONGODB_WRITE_ERROR_COUNT`); the generic library log is for the metric/trace, this
+          one is for whoever is reading logs for this specific call.
+        - Nothing is written when there's nothing relevant to report. An empty/missing
+          `documents` list (or one full of falsy/empty entries) skips Mongo entirely, so callers
+          can call this unconditionally and get `None` back for "no metadata this time" instead
+          of deciding upfront whether there's something worth saving.
+
+        Takes a *list* of documents, not a single one: each caller contributes its own document
+        (shaped like `{'filters': [...]}`), and this flattens every `filters` entry across all of
+        them into one `prediction_metadata` document before the single insert. Today only one
+        gate ever contributes a document per prediction cycle (the gate chain short-circuits on
+        the first non-`None` `path_flag`), but the list shape means this activity won't need to
+        change again once more than one source contributes metadata for the same cycle.
+
+        `insert(...)` doesn't hand back the inserted document's `_id`, so it is generated here,
+        client-side, before the insert, as a plain string (not a BSON ObjectId) — matching this
+        codebase's convention of string `_id`s (e.g. the `models` collection) and the 24-hex-char
+        size of the `predictions.metadata_id` Postgres column that will reference it.
+
+        Args:
+            input_data: Dict with:
+                - documents (list[dict[str, Any]]): Metadata payloads to combine, each shaped
+                  like `{'filters': [...]}`. Missing/empty, or entries with no `filters`, skip
+                  the write entirely.
+                - metadata (dict): Workflow metadata for contextual logging.
+
+        Return:
+            The generated id, or `None` when there's nothing to write, Mongo isn't configured, or
+            the insert failed.
+        """
+        metadata = input_data['metadata']
+        documents = input_data.get('documents') or []
+
+        filters = [
+            entry for document in documents if document for entry in document.get('filters', [])
+        ]
+
+        if not filters or self.mongo_repository is None:
+            return None
+
+        generated_id = str(ObjectId())
+
+        try:
+            self.mongo_repository.insert(
+                self._PREDICTION_METADATA_COLLECTION,
+                {'filters': filters, '_id': generated_id},
+                metadata,
+            )
+        except Exception as e:
+            self.error(f'Failed to write prediction metadata: {e}', metadata)
+            return None
+
+        return generated_id